Question

The average number of days that a house was on the market in Austin, Texas, in January 2013 was 71 days. Assume the time on the market follows an exponential probability distribution.
a. What is the probability that a randomly selected house will be on the market less than 50 days?
b. What is the probability that a randomly selected house will be on the market between 70 and 100 days?
c. What is the probability that a randomly selected house will be on the market exactly 80 days?
d. Use Excel to verify the results from parts a and b.
e. What is the standard deviation for this distribution?